Billing paper or billing sheets form the foundation for recording measured quantities in building works, facilitating the accurate preparation of bills of quantities. Quantity surveyors in Kenya rely on these documents to systematically capture and transfer measurements from site to tender documents, ensuring transparent and verifiable costing. Mastery of billing sheet preparation and quantity transfer is essential to uphold professional standards and support effective contract administration.

5.1 Billing paper/sheet

Billing sheets serve as the intermediary documents used on-site or in the office to note down quantities measured for various building elements. They allow quantity surveyors to organise and summarise measurements before transferring them into formal bills of quantities, which are then priced for tendering or valuation purposes.

5.1.1 Preparation of billing sheet/paper quantities

Billing sheets are structured documents that capture the detailed measurements of building works in an organised manner. Preparing these sheets requires accuracy, clarity, and consistency to ensure the quantities recorded can be reliably used for costing and payment.

The process of preparing billing sheets involves the following key steps:

1. Identify the work section: Begin by clearly indicating the work section or trade (e.g., concrete works, brickwork, finishes) on the billing sheet to ensure proper categorisation.

2. Record item descriptions: For each measured item, write a clear description referencing the relevant drawing or specification clause to avoid ambiguity.

3. Write measurements and units: Enter the measured dimensions (length, width, height, thickness) with correct units (meters, square meters, cubic meters) as per the measurement rules.

4. Calculate quantities: Use the measurements to compute the quantities, applying the appropriate formulas for area, volume, or count.

5. Include references or remarks: Add any relevant notes such as measurement date, location on site, or measurement conditions to provide context.

6. Review and verify: Cross-check the recorded quantities against the field measurements and drawings for accuracy before transferring.

Worked Examples

Example 1: A quantity surveyor measures a rectangular slab of dimensions 6 m by 4 m with a thickness of 0.15 m. Calculate the volume to record on the billing sheet.

Given: Length = 6 m, Width = 4 m, Thickness = 0.15 m$$\text{Volume} = \text{Length} \times \text{Width} \times \text{Thickness}$$$$= 6 \times 4 \times 0.15$$$$= 3.6 \text{ m}^3$$ Answer: 3.6 m³

Example 2: A wall measuring 10 m long and 3 m high is constructed using bricks. Calculate the wall area for billing.

Given: Length = 10 m, Height = 3 m$$\text{Area} = \text{Length} \times \text{Height}$$$$= 10 \times 3$$$$= 30 \text{ m}^2$$ Answer: 30 m²

Example 3: A window opening of dimensions 1.2 m by 1.5 m needs to be deducted from the wall area. Calculate the opening area.

Given: Length = 1.2 m, Height = 1.5 m$$\text{Area} = 1.2 \times 1.5$$$$= 1.8 \text{ m}^2$$ Answer: 1.8 m²

Example 4: Calculate the net wall area after deducting the window opening from the wall area in Example 2.

Given: Wall area = 30 m², Window opening = 1.8 m²$$\text{Net area} = 30 - 1.8$$$$= 28.2 \text{ m}^2$$ Answer: 28.2 m²

Example 5: A concrete column has a square cross-section 0.3 m by 0.3 m and a height of 3 m. Calculate the volume.

Given: Side = 0.3 m, Height = 3 m$$\text{Volume} = \text{Side} \times \text{Side} \times \text{Height}$$$$= 0.3 \times 0.3 \times 3$$$$= 0.27 \text{ m}^3$$ Answer: 0.27 m³

Example 6 (Kenyan Context): A quantity surveyor from Kenya National Highways Authority (KeNHA) measures a reinforced concrete beam of length 8 m, width 0.25 m, and depth 0.4 m for a road bridge project. Calculate the volume to record on the billing sheet.

Given: Length = 8 m, Width = 0.25 m, Depth = 0.4 m$$\text{Volume} = \text{Length} \times \text{Width} \times \text{Depth}$$$$= 8 \times 0.25 \times 0.4$$$$= 0.8 \text{ m}^3$$ Answer: 0.8 m³

5.1.2 Transfer of booked quantities

Transferring booked quantities from billing sheets to the bill of quantities requires careful verification and systematic recording to maintain accuracy and traceability. This process forms the link between site measurements and formal cost documentation.

The transfer process typically involves the following steps:

1. Verify quantities: Reconcile the quantities recorded on the billing sheets with site measurements and drawings to confirm accuracy.

2. Match work sections: Ensure that the billing sheet items correspond exactly to the relevant work sections and descriptions in the bill of quantities.

3. Enter quantities into the bill: Carefully transfer the quantities into the bill of quantities, maintaining the same units and item references.

4. Check for omissions or duplications: Review the bill to detect any missing items or duplicated quantities.

5. Record transfer dates and officer details: Note the date of transfer and the responsible quantity surveyor to maintain accountability.

6. File and archive billing sheets: Keep the original billing sheets securely for future reference or audit.

Worked Examples

Example 1: A billing sheet records 12 m³ of concrete for a slab. Transfer this quantity into the bill of quantities.

Given: Concrete quantity = 12 m³

• Verify concrete section in the bill
• Locate the concrete slab item
• Enter 12 m³ in the quantity column
  Answer: 12 m³ entered in the bill

Example 2: A wall area of 25 m² is measured on the billing sheet. The bill of quantities has the same wall item. Transfer the quantity.

Given: Wall area = 25 m²

• Confirm wall description matches
• Enter 25 m² in the bill under wall works
  Answer: 25 m² entered in the bill

Example 3: Two billing sheets list 8 m and 10 m lengths for different plumbing pipes. Transfer to the bill.

Given: Pipe lengths = 8 m and 10 m

• Identify pipework section in bill
• Enter 8 m and 10 m separately or sum as required
  Answer: 18 m total pipe length recorded

Example 4: A billing sheet has a quantity of 15 m² for tiling. Transfer to the bill and verify units.

Given: Tiling area = 15 m²

• Confirm units match
• Enter 15 m² in the finishing section of the bill
  Answer: 15 m² entered

Example 5: A billing sheet records 0.5 m³ of excavation. Transfer to the bill.

Given: Excavation volume = 0.5 m³

• Locate excavation item in bill
• Enter 0.5 m³ in quantity column
  Answer: 0.5 m³ recorded

5.1.3 Price bill of quantities

Pricing the bill of quantities involves applying rates to the measured quantities to determine the total cost for each item and the overall project. This step is crucial for tendering, valuation, and cost control in construction projects.

The procedure for pricing a bill of quantities includes:

1. Confirm quantities: Verify the accuracy and completeness of the quantities before pricing.

2. Obtain current rates: Source up-to-date unit rates from suppliers, subcontractors, or standard rate books relevant to the Kenyan market.

3. Apply unit rates: Multiply each quantity by its respective unit rate to calculate the item cost.

4. Calculate total sums: Sum the item costs for each work section and the entire bill.

5. Include preliminaries and contingencies: Add costs for site preliminaries, overheads, and contingencies as appropriate.

6. Review and adjust: Check calculations for errors and adjust rates or quantities if necessary to reflect project specifics.

Worked Examples

Example 1: Price 10 m³ of concrete at Ksh 6,000 per m³.

Given: Quantity = 10 m³, Rate = Ksh 6,000/m³
Cost = Quantity × Rate
Cost = 10 × 6,000
Cost = Ksh 60,000
Answer: Ksh 60,000

Example 2: Price 50 m² of brickwork at Ksh 1,200 per m².

Given: Quantity = 50 m², Rate = Ksh 1,200/m²
Cost = 50 × 1,200
Cost = Ksh 60,000
Answer: Ksh 60,000

Example 3: Price 25 m length of steel reinforcement bars at Ksh 120 per meter.

Given: Quantity = 25 m, Rate = Ksh 120/m
Cost = 25 × 120
Cost = Ksh 3,000
Answer: Ksh 3,000

Example 4: Price a plastering area of 40 m² at Ksh 350 per m².

Given: Quantity = 40 m², Rate = Ksh 350/m²
Cost = 40 × 350
Cost = Ksh 14,000
Answer: Ksh 14,000

Example 5: Calculate total cost for 15 m³ excavation at Ksh 800 per m³ plus 10% contingency.

Given: Quantity = 15 m³, Rate = Ksh 800/m³
Base cost = 15 × 800 = Ksh 12,000
Contingency = 10% of 12,000 = Ksh 1,200
Total cost = 12,000 + 1,200 = Ksh 13,200
Answer: Ksh 13,200

Chapter Summary

This chapter focused on the detailed process of preparing and managing bill measured quantities in building works. It began with the preparation of billing sheets or papers, emphasizing the accurate recording of quantities for various construction items. The transfer of these booked quantities into organized documents was discussed to ensure clarity and proper tracking. Attention was then given to the price bill of quantities, which involves assigning costs to the measured quantities to facilitate budgeting and payment. The chapter also explored emerging technologies transforming quantity measurement practices, starting with Building Information Modeling (BIM), which enhances precision and visualization. Cloud-based collaboration platforms were highlighted for their role in improving communication and data sharing among project stakeholders. The use of Artificial Intelligence and Machine Learning was presented as a means to automate and optimize quantity surveying tasks. Finally, mobile technology was recognized for enabling real-time data capture and remote access to measurement information on construction sites.